In the Network and Internet Centre (assuming that still exists in W11?) is your network set to PRIVATE or PUBLIC?

Yes, it still exists, a bit modified.  A good tip. Changed to private and it works. Many thanks.

I am glad it is sorted.  I have been caught out myself by updates to W10 that reset my network to Public from Private.

I have the same problem to connect to Sonos on a W11 PC what is a company pc. I can’t switch to a private network due the admin setting by administrator. My network is a public one. What else can be the problem?

You could install a “Travel Router”. These are designed for similar situations where hotel guests need more network support than a single device accessing the Internet. (for example a wireless printer).

I would suggest that SONOS finds a solution while it works perfect under W10. I will not invest in more Router devices only to have a connection with my PC to SONOS. 

There is nothing for Sonos to solve here (except maybe a better error message saying “switch your network to private”, like my Windows app does). Sonos requires that your local network allows data to pass freely between devices.